1. Field of Invention
The present invention relates to a medical pump which has its pumping rate and pumping interval controlled by a magnetic label. This label visually alters the scales on the various manual controls, and, via the positions of magnets which are sensed by Hall Effect sensors within the pump, communicates a value to the pump which takes into account various factors relating to the desired pharmaceutical product infusion.
2. Description of the Prior Art
Medical pumps with infusion parameters controlled by manual dial settings, microprocessors, and electrical devices are well-known in the prior art. For example, U.S. Pat. Nos. 3,701,345 and 4,320,757 disclose apparatus with electrical drive systems for injecting controlled amounts of fluid into a patient. However, these references require the user to be cognizant of several variables such as the concentration of the pharmaceutical product within solution, the desired infusion rate of the pharmaceutical product, the weight of the patient, the total amount of pharmaceutical product desired to be injected into the patient either on a total or per unit of weight or mass, and even the cross-sectional area of the plunger of the ampule so as to calculate a desired velocity and total displacement of the plunger within the ampule of the syringe. Moreover, the user would have to be cognizant even of the units of all of these variables so as to not make a calculative error. Any of these calculative errors could be disastrous to the patient.
References which show an injection system with a programmable means responsive to a keyboard include U. S. Pat. Nos. 4,529,401; 4,624,661; 4,681,563; and 4,722,734. However, these systems still require several keystrokes on the part of medical personnel with a wide range of skill levels, some of whom may find such a computer-like device intimidating. Further, the exhaustion and hurried pace of many medical situations are not conducive to the consistently accurate programming needed for such devices. Further, the difficulty in operating these devices is compounded when, after the infusion starts, medical personnel realize that the dose must be adjusted to accommodate the patient's metabolism, tolerance, and sensitivities with respect to the pharmaceutical product being infused.
U.S. Pat. No. 4,741,732 uses a complicated programming scheme to effect generalized infusion rate profiles of a pharmaceutical product so as to maintain a constant pharmaceutical product concentration within the patient. This device may still have the deficiencies listed in the previous paragraph in that a manual entering of all of the data needed for a particular pharmaceutical product concentration, patient body weight, plunger cross section is very error prone for exhausted or hurried medical personnel. These deficiencies are mitigated, only in part, by including an EPROM (electrically programmable read-only memory) which includes instructions and/or data in machine or object language form relating to the general characteristics of the desired time-dependent infusion rate profile. Even when using the EPROM device, this device is complicated and is directed more toward delivering complex time-dependent infusion rate profiles rather than providing a simple, "user-friendly" device with visually verifiable controls, for infusing a given dose of a pharmaceutical product to a patient.